(19)
(11) EP 0 722 233 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.11.1997 Bulletin 1997/48

(43) Date of publication A2:
17.07.1996 Bulletin 1996/29

(21) Application number: 95309322.6

(22) Date of filing: 20.12.1995
(51) International Patent Classification (IPC)6H04J 3/06, G06F 1/14
(84) Designated Contracting States:
DE FR GB

(30) Priority: 21.12.1994 US 360508

(71) Applicant: Hewlett-Packard Company
Palo Alto, California 94304 (US)

(72) Inventors:
  • Eidson, John C.
    Palo Alto, CA 94303 (US)
  • Dara-Abrams, Joseph A.
    Los Altos, CA 94024 (US)
  • Woods, Stanley P.
    Santa Clara, CA 95051 (US)
  • Cutler, Leonard S.
    Los Altos Hills, CA 94022 (US)
  • Giffard, Robin P.
    Los Altos, CA 94024 (US)
  • Johnson, James L.
    Scotts Valley, CA 95066 (US)

(74) Representative: Jehan, Robert et al
Williams, Powell & Associates, 34 Tavistock Street
London WC2E 7PB
London WC2E 7PB (GB)

   


(54) Timing in a data communications network


(57) A data communication network comprises a local clock (22) within a node (2) of the network which may be synchronized and syntonized by any node in the network. Each node contains a time packet detector (6) that detects and recognizes timing data packets and produces a recognition signal. Each node has a time server (10) that includes the local clock (22). The time server records the time of the recognition signal. The recorded time is used for correcting the local clocks of the various nodes (2) in the network. A transfer device such as a gateway, a bridge or a router may include a time server and a time packet detector to correct for the transit time of a time packet through such transfer device. The time packet detector (6) is connected at the point of final encoding for transmission or recovery of the clock and data.







Search report